Usually, in the electronic element unit having the connecting terminal of the electronic element connected to the electrode of the circuit board by the solder bump, an electronic element unit is known in which before a connecting terminal of an electronic element is connected to an electrode of a circuit board, or after the connecting terminal is connected to the electrode, a thermosetting resin is supplied to a part between the electronic element and the circuit board to thermally solidify the thermosetting resin so that a columnar resin bond part is formed between the electronic element and the circuit board so as to strongly connect the electronic element to the circuit board (patent literature 1). Further, an electronic element unit is also known in which an inorganic filler such as silica powder is previously added to a thermosetting resin so that a modulus of elasticity of the thermally solidified thermosetting resin is high (hard) to increase a bonding force between an electronic element and a circuit board and improve a bonding reliability.